Polarization-sensitive infrared image sensor including a plurality of optical fibers
| DWPI Title: Polarization-sensitive infrared image sensor i.e. snapshot polarimeter, for computer, has two-dimensional array of infrared photodetectors located proximate to exit end of two-dimensional array of optical fibers |
| Abstract: A polarization-sensitive infrared image sensor (also termed a snapshot polarimeter) utilizing a 2-D array of polarizers to filter infrared light from a scene according to polarization, and a 2-D array of photodetectors (i.e. a focal plane array) to detect the filtered infrared light and generate polarization information which can be used to form a polarization-sensitive image of the scene. By forming each polarizer on an optical fiber in a fiber optic faceplate, the polarizers can be located facing a 2-D array of retarders to minimize diffraction effects of the infrared light. The optical fibers also guide the filtered infrared light to the photodetectors to reduce cross-talk in the polarization information. The polarizers can be formed as wire grid polarizers; and the retarders can be formed as subwavelength surface-relief gratings. |
| Use: Polarization-sensitive infrared image sensor i.e. snapshot polarimeter, for a computer. |
| Advantage: The sensor allows smaller lateral dimensions of the exit end of each optical fiber with a minifying taper to match size of the photodetectors and to prevent cross-talk between adjacent photodetectors so as to improve extinction ratio of the sensor. The sensor allows anti-reflection coating to be provided on an exit side of a fiber optic faceplate so as to reduce fresnel reflection loss of the infrared light transmitted through the optical fibers. The photodetectors are cooled to low temperature to provide enhanced sensitivity for detection of the infrared light and to provide a reduced noise level in electrical output signals. |
| Novelty: The sensor (10) has a two-dimensional (2D) array of optical fibers (14) located proximate to a 2D array of polarizers (12) to receive filtered infrared light (100) from each polarizer at an entrance end (16) of the 2D array of optical fibers. a 2D array of infrared photodetectors (20) i.e. infrared focal plane array, is located proximate to an exit end (18) of the 2D array of optical fibers, where each infrared photodetector detects the filtered infrared light from one of the optical fibers to generate an electrical output signal containing polarization information for a pixel of a scene. |
| Filed: 2/3/2009 |
| Application Number: US2009364537A |
| Tech ID: SD 10848.0 |
| This invention was made with Government support under Contract No. DE-NA0003525 awarded by the United States Department of Energy/National Nuclear Security Administration. The Government has certain rights in the invention. |
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